The world’s first drug to delay the onset of type 1 diabetes is to be made available on the NHS in England and Wales, in the biggest breakthrough in tackling the disease for more than a century.

Millions of people have type 1 diabetes worldwide, which typically emerges during childhood or adolescence, and occurs when the pancreas makes little or no insulin. Insulin is a hormone the body uses to allow glucose to enter cells to produce energy.

The immunotherapy, teplizumab, does not cure type 1 diabetes, but postpones its onset for as long as three years, according to the National Institute for Health and Care Excellence (Nice), which gave the drug the green light on Tuesday.

Its arrival marks a huge step forward. The therapy gives those deemed at high risk of symptomatic type 1 (stage 3) diabetes the chance to delay its onset for the first time in the history of the disease.

By delaying the onset, people will benefit from years of extra time before facing the heavy demands of lifelong diabetes management. Children and teenagers in particular will have more time to reach key developmental milestones before that point.

Nice approved the drug for use in adults and children aged eight and above with early, pre-symptomatic type 1 diabetes (stage 2), enabling them to live more normal lives for longer.

The only other treatment for the disease – insulin – was discovered 105 years ago and does not alter the course of the disease. It simply replaces what patients are missing.

“Today’s landmark approval of teplizumab marks the start of a new age of type 1 diabetes treatment,” said Dr Elizabeth Robertson, director of research at the charity Diabetes UK. “For the first time in 100 years, we are moving beyond insulin, with a medicine that targets the root cause of the condition.

“This is an extraordinary moment for celebration in the type 1 diabetes community, and represents a shift towards a future where type 1 diabetes can be prevented altogether.”

Teplizumab, also known as tzield and made by Sanofi, will offer those in the early stages of type 1 diabetes years “free from the relentless demands” of managing the condition with insulin, as well as valuable time to prepare, Robertson said.

“Detecting type 1 diabetes early, before symptoms appear, is key to unlocking these benefits and our focus now is ensuring fair and equitable access for everyone who is eligible.”

Teplizumab trains the immune system to stop attacking pancreatic cells. It is given through a drip into a vein once a day – which takes about 30 minutes – for 14 days in a row.

The dose starts low and gradually increases. Once the 14-day course is complete, that is the end of the treatment.

Karen Addington, chief executive of the diabetes charity Breakthrough T1D, said the drug’s approval marked an “incredible moment” for the type 1 community. “For the first time, we have an immunotherapy that can delay the onset of symptomatic type 1 diabetes.

“If it were your child or someone you love, you would want to do everything possible to give them more years without the daily burden of managing this relentless condition. We now have a treatment that can help make that possible.”

Sanofi has agreed a commercial arrangement with NHS England, the Guardian understands, meaning teplizumab will be available to the NHS at a confidential discounted price.

Helen Knight, director of medicines evaluation at Nice, said the decision to approve the drug was rigorous, transparent and based on the best available evidence, striking a balance between clinical benefit and value for taxpayers.

“This is a genuinely exciting recommendation. For the first time, we have a treatment that can give people diagnosed at an early stage of type 1 diabetes precious extra time before they need to manage the full demands of the condition.”